The use of tetrakis(dialkylamide or diarylamide) derivatives of titanium in the Ziegler-Natta catalysis of .alpha.-olefins has been described by Firestone Tire & Rubber Co. in British Pat. No. 969,074, published Sept. 9, 1964. These polymerizations, however, have been conducted at low temperatures, i.e. at temperatures up to about 150.degree. C. It would be desirable to have catalysts which are operable at higher temperatures so as to be useful in the solution polymerization of .alpha.-olefins. The present invention provides catalyst compositions which are useful for the polymerization of olefins at both low and high temperatures under either slurry or solution polymerization conditions and also provides catalyst compositions for producing polymers of narrow or broad molecular weight distributions, depending on the compositions employed. One particular advantage of the catalysts of the present invention over those of the prior art is the production of high surface area supported catalysts without the use of energy intensive ball milling and/or grinding of the supported compositions. Another advantage is a reduction in the number of additives required to produce efficient catalysts as required in the prior art employing tetrakis(dimethylamino)silane solutions in catalyst compositions. Another advantage is the preparation of high efficiency catalyst compositions which eliminates the need to remove catalyst residues from the resin products.